The present invention relates to mechanisms that support seats of vehicles such that the seats slide.
A typical vehicle""s seat support mechanism permits a front seat to slide forward when its seatback is folded over, thus making it easy for a passenger to enter or exit the rear of the passenger compartment of a two-door vehicle. Japanese Unexamined Patent Publication No. 8-295162 describes an example of such mechanism. The mechanism includes upper rails for supporting a seat and lower rails secured to the vehicle""s floor, when a reclining device folds over the seatback, the upper rails slide forward along the lower rails in accordance with the folding angle of the seatback.
More specifically, the sliding of the upper rails is normally restricted. The mechanism permits the upper rails to slide it the folding angle of the seatback exceeds a predetermined value. Thus, the upper rails, which supports the seat, slides even when using the seatback as a table by folding over the seatback until its rear side becomes substantially horizontal. In such case, the seatback cannot be used as intended since the seat is unstable.
Japanese Unexamined Patent Publication No. 9-286264 describes an example of a structure that solves the problem. In the described structure, each seat includes a pair of shafts. A seatback inclines about the shafts. The two shafts are located on the same side of the seat. If necessary, the two shafts may be provided on each side of the seat. More specifically, one of the shafts, or a first shaft, is located in a cushion of the seat and is used to change the inclination of the seatback, such as when folding over the seatback to move the seat forward. The other shaft, or a second shaft, is located in the seatback and used to change the inclination of the seatback, such as when using the seatback as a table. The seat slides forward when the seatback folds over about the first shaft. In contrast, the sliding of the seat is restricted when the seatback folds over about the second shaft, This enables the rear side of the seatback to be used as intended.
However, in this structure, the second shaft is located at a position higher than the first shaft. Thus, when the rear side of the seatback is substantially horizontal and used as a table, the seatback is placed on the seat cushion. This restricts the space in the passenger compartment above the seatback. Further, the two shafts enlarge the seat and increases cost.
Accordingly, it is an objective of the present invention to provide a smaller seat support mechanism that permits a seatback to fold over to a substantially horizontal state and stabilizes the seat so that the seatback may be used as a table. It is a further objective of the present invention to provide a seat support mechanism that reduces cost and provides more space above the seatback when the seatback is used as a table.
To achieve the foregoing and other objectives and in accordance with the purpose of the present invention, the invention provides a structure for supporting a seat of a vehicle. The seat includes a seatback. The seat is slidable relative to a floor of the vehicle, and the seatback inclines forward with respect to the seat. The structure includes a seat cushion arranged on the seat. The seat cushion is movable between a normal position at which a passenger may sit on the seat and a lifted position at which the seat cushion is moved from the normal position. A locking member selectively permits and prohibits the sliding of the seat. A first actuating member controls the locking member. The first actuating member is capable of releasing the locking member to permit the sliding of the seat when the seat cushion is located at the normal position and the seatback is inclined forward with respect to the seat. The first actuating member is incapable of releasing the locking member when the seat cushion is located at the lifted position and the seatback is inclined forward with respect to the seat.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.